The generation of acoustic energy to produce underwater pressure fields is already known, involving the use of spark gaps between electrodes or use of an air gun in order to obtain pressure impulses singly or in rapid succession within a narrow band frequency spectrum. However, in connection with an underwater explosion, both its narrow frequency band signature and pressure time history changes with environmental conditions, location of the explosive charge and location of measurement so as to affect the pressure field to be simulated. The complexities of time history and frequency spectrum associated with underwater explosions are such that they cannot be matched by use of spark gap or air gun methods for explosive pressure field simulation purposes. Also, such known spark gap and air gun methods produce extraneous effects such as light flashes or bubbles which adversely affect simulation of explosion pressure fields in large volumes of seawater. It is therefore an important object of the present invention to provide apparatus and process to reproduce and record at some underwater location of interest an accurate simulation of remotely located explosion pressure fields useful for example in assessing potential damage to marine mammal hearing.